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NeilBlanchard

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Messages
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I am responding to the Five Critical Changes post on Plugin Cars: http://www.plugincars.com/five-critical-changes-next-nissan-leaf-130381.html

My list of 5 improvements for the Leaf (or any EV!):

1) Lower aerodynamic drag, by lowering the Cd from 0.28 (claimed, or 0.32 measured by Car&Driver: http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test" onclick="window.open(this.href);return false; ) down to 0.21-0.23. This is entirely possible with the same general chassis for, as shown by the Renault Eolab. Make the active elements fixed in their lower drag positions, and the range of the Leaf would be increased.

A lot. Possibly as much as 2X what it is now.

This can be done by moving the cabin forward, and making the back a bit longer - and taper the top and sides (and the underside) so the air is able to flow back into the place it was before the car punched its way through. The rear wheel track needs to be (slightly) narrower than the front - when the car is lower drag - it coasts much better. (See #4 below.)

2) Direct heating windshield defroster. This would make the penalty of running the defroster almost negligible.

3) Reconfigure the battery pack to provide more rear seat legroom. Put some additional modules under the hood, and under the hatch floor.

Make the seats much slimmer - if they are well designed, they will be more comfortable, weigh less, and take up a lot less room inside the car - making that space available for the people in the car.

4) Make coasting the default, and add 3 levels (or continuously variable of) regen controlled by the shifter, or paddles on the steering wheel. This would encourage ecodriving, and increase the range by using the kinetic energy of the moving car the most efficient way possible - by using it to move the car forward.

Regen is great - for slowing the car.

5) Use video mirrors. (And if required, put tiny optical mirrors, as well.) This will reduce the frontal area and the Cd - and it will eliminate the need for the bulging headlights. I have been driving with video mirrors for about 6 years now, and they work very well, and they are better than optical mirrors in many ways. Mine are inexpensive backup cameras, so with better "F stop" controls, they will be better than optical mirrors in virtually every way.

I think these changes will make the range with the same battery it has today much longer than it is now. If/when we get a better battery, then the range gets even longer and/or the price comes down.

It's all good.
 
NeilBlanchard said:
The rear wheel track needs to be (slightly) narrower than the front
I have a car that has this (first gen Honda Insight) and I can tell you that this sucks. The car "hunts" around on the freeway when there are grooves or other features that make the front wheels and back wheels track slightly differently. Reportedly this is even worse in the snow since the back wheels don't follow the track of the fronts. I don't think it's worth it, in my opinion. :)
 
I have to chime in, having 4 kids and if just I am driving them around, having that huge "hump" in the center back on the floor just for a small battery fuse / disconnect is crazy. There is tons of room in there and it could have been much lower and narrower or just move the disconnect somewhere else to give the kids leg room back there. why have a three seat configuration with no foot well for the center person? Not a big deal, I just don't like wasted space, I was tempted to cut it all our and make it smaller, but it would look like I did just that :)
 
NeilBlanchard said:
1) Lower aerodynamic drag, by lowering the Cd from 0.28 (claimed, or 0.32 measured by Car&Driver: http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test" onclick="window.open(this.href);return false; ) down to 0.21-0.23. This is entirely possible with the same general chassis for, as shown by the Renault Eolab. Make the active elements fixed in their lower drag positions, and the range of the Leaf would be increased.
A lot. Possibly as much as 2X what it is now.
I don't think improving the Cd would double the range. Not even close. I suspect it might add 10 miles of range. But even then, that's only on the highway where drag really matters. Driving around in city traffic it won't make a scrap of difference. If they are going to make any change to the body, I would hope they would do so with the aim of making the car more attractive to the mainstream buyer.
3) Reconfigure the battery pack to provide more rear seat legroom. Put some additional modules under the hood, and under the hatch floor.
It isn't really practical or cost effective to put a few additional modules outside of the main battery pack.
4) Make coasting the default, and add 3 levels (or continuously variable of) regen controlled by the shifter, or paddles on the steering wheel. This would encourage ecodriving, and increase the range by using the kinetic energy of the moving car the most efficient way possible - by using it to move the car forward.
Totally disagree here. I prefer the way Tesla and BMW are doing it. Essentially, the brake is for friction brakes only, the regen comes from letting off of the throttle. I drive our Volt and Leaf in "B mode" 100% of the time. I wish it had MORE regen, actually.
5) Use video mirrors. (And if required, put tiny optical mirrors, as well.) This will reduce the frontal area and the Cd - and it will eliminate the need for the bulging headlights. I have been driving with video mirrors for about 6 years now, and they work very well, and they are better than optical mirrors in many ways. Mine are inexpensive backup cameras, so with better "F stop" controls, they will be better than optical mirrors in virtually every way.
In sticking with mainstream appeal... regular mirrors should remain.
 
While I would like to see a better Cd, my concern is that tapering the car would drastically lower the space and utility of the hatch. I only drive hatchbacks because of the utility. For me, the LEAF hatch opening is already a bit too small. If it were turned into a Citroen-style vehicle it would be even worse. Lowering the car to reduce Cd, as is sometimes done, would also be a step backward. The decent ground clearance or the LEAF helps with rough roads and snow (which also might make wheel fairings impractical).

The car has to be practical in order to sell, I would guess. Turning it into a nifty super-low-Cd science project isn't necessarily a way to do that.
 
NeilBlanchard said:
I am responding to the Five Critical Changes post on Plugin Cars: http://www.plugincars.com/five-critical-changes-next-nissan-leaf-130381.html

My list of 5 improvements for the Leaf (or any EV!):

1) Lower aerodynamic drag, by lowering the Cd from 0.28 (claimed, or 0.32 measured by Car&Driver: http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test" onclick="window.open(this.href);return false; ) down to 0.21-0.23. This is entirely possible with the same general chassis for, as shown by the Renault Eolab. Make the active elements fixed in their lower drag positions, and the range of the Leaf would be increased.

A lot. Possibly as much as 2X what it is now.

This can be done by moving the cabin forward, and making the back a bit longer - and taper the top and sides (and the underside) so the air is able to flow back into the place it was before the car punched its way through. The rear wheel track needs to be (slightly) narrower than the front - when the car is lower drag - it coasts much better. (See #4 below.)

2) Direct heating windshield defroster. This would make the penalty of running the defroster almost negligible.

3) Reconfigure the battery pack to provide more rear seat legroom. Put some additional modules under the hood, and under the hatch floor.

Make the seats much slimmer - if they are well designed, they will be more comfortable, weigh less, and take up a lot less room inside the car - making that space available for the people in the car.

4) Make coasting the default, and add 3 levels (or continuously variable of) regen controlled by the shifter, or paddles on the steering wheel. This would encourage ecodriving, and increase the range by using the kinetic energy of the moving car the most efficient way possible - by using it to move the car forward.

Regen is great - for slowing the car.

5) Use video mirrors. (And if required, put tiny optical mirrors, as well.) This will reduce the frontal area and the Cd - and it will eliminate the need for the bulging headlights. I have been driving with video mirrors for about 6 years now, and they work very well, and they are better than optical mirrors in many ways. Mine are inexpensive backup cameras, so with better "F stop" controls, they will be better than optical mirrors in virtually every way.

I think these changes will make the range with the same battery it has today much longer than it is now. If/when we get a better battery, then the range gets even longer and/or the price comes down.

It's all good.

1) I think the leaf should had 1 inch less ground clearance (although I see why they played it safe with a high one) 2 inch lower roof line with a thinner battery under the floor (although I'm 6'4 and would still fit with 2 inches less but it'd be tight), about 3 inches longer wheel base and more slope to the rear hatch, thinking a slope like the back of the new Mazda 3 hatch which has an almost identical footprint (within an inch all round) with 4 inches less height and 96/22 cu ft interior/trunk vs the leaf 92/24. I would bet that 2 cu ft trunk is the high view blocking area of the hatch that isn't that practical. The void spare tire space should have been battery and for the markets that need a spare tire let it eat trunk space. After all the customer can always take it out after they buy it and how many are sold there?

A dealer add on part for a rear wheel cover would be pretty cool too.

3) I don't think this is just a reconfigured pack issue. A longer wheelbase could achieve the same thing. I chose the leaf over the FFE (2 inches less wheelbase and 4 inches less length) for 3 reasons, rear seat room for kids, QC, test drive (no Ford dealer had one). They have all the batteries in the trunk and still have less leg room, I think the seats were bigger too though. Although not a sales feature for me the bigger trunk is one thing the leaf has over the FFE and Volt. It's the perfect place to offer an added extra range battery but not a good place to put the standard battery. Side note if the FFE had been $6000 less like it is now I would have bought it over the leaf.


5) Video mirrors, the only downside I see is in salt/snow conditions the sensor is so small that a tiny bit of salt takes up pretty much the whole camera. It would be pretty cool if there were pop out physical mirrors that extend only when you signal to compliment the video ones. Then you'd have low drag and when they same conditions make a regular mirror dirty your pop out mirrors would be almost always clean. They could also be always out at low speed. The rear camera on the leaf is pretty useless around now except for the fact that I've got in the habit of cleaning it off every time I park at work and take out the 120v cable. Pop out rear cameras would be nice but as the dealer told me it doesn't work as well with around view, the other option would be a camera that's behind the glass portion of the wiper blade.


JeremyW said:
NeilBlanchard said:
The rear wheel track needs to be (slightly) narrower than the front
I have a car that has this (first gen Honda Insight) and I can tell you that this sucks. The car "hunts" around on the freeway when there are grooves or other features that make the front wheels and back wheels track slightly differently. Reportedly this is even worse in the snow since the back wheels don't follow the track of the fronts. I don't think it's worth it, in my opinion. :)

I also have an insight and drove it through last winter which was a pretty bad one for us. It was a GREAT car in the snow!

I think the problem with the rear isn't because it's narrow it's the suspension is so loose back there and it's pretty light weight, also I understand the alignment is set up for optimum efficiency without much or any toe in that gives high speed stability and resistance to pulling. Just like Porsche can make a rear engine car handle not just well but amazing a trait can be engineered out if they want to keep it bad enough.

Does anyone know what the leaf alignment is set up like? Are there any gains to be made by going to a 0 toe in the rear?
 
dgpcolorado said:
While I would like to see a better Cd, my concern is that tapering the car would drastically lower the space and utility of the hatch. I only drive hatchbacks because of the utility. For me, the LEAF hatch opening is already a bit too small. If it were turned into a Citroen-style vehicle it would be even worse. Lowering the car to reduce Cd, as is sometimes done, would also be a step backward. The decent ground clearance or the LEAF helps with rough roads and snow (which also might make wheel fairings impractical).

The car has to be practical in order to sell, I would guess. Turning it into a nifty super-low-Cd science project isn't necessarily a way to do that.

I wouldn't call the leaf ground clearance decent, it's high. There's no other way to describe it. It's 6.3 inches on a car that needs to be aerodynamic. To reference the car and driver drag queens again the leaf is the car with the most to gain from good aero and it finished last. Maybe what Nissan needs is a sporty sedan and outback style hatch offering. If you buy the hatch you know you give up range.

The volt, Prius and Mercedes CLA all sell well and all beat the leaf. The volt and prius both have a hatch. I have a prius and a leaf. I used the prius to pick up a dish washer, a 300cc gas snow blower and a washing machine. It's much better for loading than the leaf with 2 cu ft less actual trunk space. Making a proper designed rear doesn't have to lower the utility of the hatch if they care enough to engineer a good opening. The one they have now is all show and no go, it's much smaller than it needs to be to look like it flows. I've always felt a trunk opening is somewhere where style doesn't belong, square is key and split openings (up/down) are under utilized in this industry.

They could also do what the leaf did and keep the high ground clearance with a low chin spoiler that can be swapped out for a higher one if the rubbing bothers you.

I think 0.21-0.23 cd is too much to ask for in the next leaf but at least a tie to the prius shouldn't be too much.
 
adric22 said:
NeilBlanchard said:
1) Lower aerodynamic drag, by lowering the Cd from 0.28 (claimed, or 0.32 measured by Car&Driver: http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test" onclick="window.open(this.href);return false; ) down to 0.21-0.23. This is entirely possible with the same general chassis for, as shown by the Renault Eolab. Make the active elements fixed in their lower drag positions, and the range of the Leaf would be increased.
A lot. Possibly as much as 2X what it is now.
I don't think improving the Cd would double the range. Not even close. I suspect it might add 10 miles of range. But even then, that's only on the highway where drag really matters. Driving around in city traffic it won't make a scrap of difference. If they are going to make any change to the body, I would hope they would do so with the aim of making the car more attractive to the mainstream buyer.


The big difference is in the actual usable range. It would matter a lot in the winter and for people who don't care to hypermile. A lot of the people coming here complaining about the leaf aren't complaining about around town 30mph range it's the people who want to do 100 miles on the highway or want to get 70 miles year round with heat.
 
Aerodynamics matter at all speeds. At just 30MPH, aero drag is slightly more than 50% of the load on the drivetrain. Aero drag is always a total loss.

Weight, on the other hand can be regained by coasting, and when you want to slow down, using regen regains somewhat less.

By the way, by having lower drag makes coasting even more effective. Extending the back longer gains storage space, as does pushing the seats forward. This is a rough 3D model of a very streamlined car (sketched by Tyler Linner) that I modeled based on his sketch combined with a ideal aerodynamic shape:

https://www.youtube.com/watch?v=EjOmQc6RqrE&list=UUL0K171ZJzmMEZaHg_-BttA&index=11

Ground clearance is required for a low drag car - ~6" minimum clearance is about ideal. With too little clearance, the air gets very turbulent, which adds drag.

We have several examples of how much a low drag design can improve range: the EV1, the Illuminati Motor Works 'Seven', and Dave Cloud's Dolphin. None of these are light, but they are all low drag. The IMW 7 goes 220+ miles on a 33kWh pack, when driving at 60-70MPH. With that kind of efficiency, today's Leaf could have ~160 mile range.

As for the practicality of a low drag design: the Prius is more practical (in my opinion) than the Leaf, and the Prius is significantly lower drag. Remove the need for cooling the engine in the Prius and the hot exhaust system, and you can drop the Cd by probably 0.01. Add rear wheel skirts, and smooth front wheel covers, and some rear track taper, video mirrors, and the Cd might even best the EV1. By having a low Cd, a larger car can have the same drag (CdA) as a smaller car: the Tesla Model S has the same drag as the Prius.
 
minispeed said:
...The volt, Prius and Mercedes CLA all sell well and all beat the leaf. The volt and prius both have a hatch.
The Prius is a good example I suppose, but the Volt is much smaller, cramped, and awkward to get into and out of. I drove a Volt for a couple of hours and it was a relief to get back into the spacious, comfortable LEAF. I've never heard of or seen the Mercedes CLA.
I have a prius and a leaf. I used the prius to pick up a dish washer, a 300cc gas snow blower and a washing machine. It's much better for loading than the leaf with 2 cu ft less actual trunk space. Making a proper designed rear doesn't have to lower the utility of the hatch if they care enough to engineer a good opening. The one they have now is all show and no go, it's much smaller than it needs to be to look like it flows. I've always felt a trunk opening is somewhere where style doesn't belong, square is key and split openings (up/down) are under utilized in this industry.
I agree that the LEAF hatch could be better designed. But with the extreme tapering, suggested by NeilBlanchard, if I understand his suggestion correctly, it would be difficult.
They could also do what the leaf did and keep the high ground clearance with a low chin spoiler that can be swapped out for a higher one if the rubbing bothers you.
I already rub the current spoiler on curb stops but my main concern is driving through snow and on dirt roads. A low clearance car tends to ride up on snow and that reduces traction IME.
I think 0.21-0.23 cd is too much to ask for in the next leaf but at least a tie to the prius shouldn't be too much.
I agree. But NeilBlanchard's main point that the Cd is important and can be improved is very well taken.

I suppose it is worth noting that the LEAF is a generation 1 EV and the next major redesign could be improved considerably. We all have our likes and dislikes so LEAF 2 won't satisfy everyone regardless of what changes are made.
 
My Top 5:

1) More battery. Just adding more cells will add weight, which can have a cascade effect, so I am hoping they have higher densities up their sleeve. 150 miles EPA range is really going to be a nice sweet spot to hit.

2) More sane environmental controls. I find the current setup to be needlessly complicated to get what I want, and you have to toggle things to see what the current state was. I'd rather have cold/hot knob instead of a temperature setting. Heck, I would prefer more knobs/levers I can blindly adjust without taking my eyes off the road to figure which button to press.

3) Tone down the goofy looks. It can still look like a distinctive Leaf with less buggy eyes and better hips. I am an introvert and would actually prefer fewer questions about my car. If you can make it a little more aerodynamic without looking bizarre I'll take it, but know that looks will matter more to the masses than to the vocal minority of frothing at the mouth hypermilers (nothing makes them happy).

4) Overhaul the displays with LINEAR readouts, maybe even a geek mode for people that passed Algebra. Currently every readout has the effect of being mangled by an unseen distortion field. Nothing is as it appears to be, from non-linear fuel bars, to non-linear capacity bars, to the overly chunky temperature bars, or the mangled GOM.

5) Offer a pro-rated 120k mile/10 year battery extra warranty beyond the 60k/5 year cliff warranty, as well as stating the battery replacement price up-front for the Leaf 2. A pro-rated warranty is needed to avoid the current 5 year/60k mile lottery with its perverse incentives. Battery degradation and replacement costs are the number one set of questions I get from friends, and mostly they are not terribly happy about what they hear

Bonus: More motor power above 30 mph. The bottom end is plenty peppy, but just gets sad by 50 mph. How about giving us 100-120 kW of power above 30 mph?
 
NeilBlanchard said:
I am responding to the Five Critical Changes post on Plugin Cars: http://www.plugincars.com/five-critical-changes-next-nissan-leaf-130381.html

5) Use video mirrors. (And if required, put tiny optical mirrors, as well.) This will reduce the frontal area and the Cd - and it will eliminate the need for the bulging headlights. I have been driving with video mirrors for about 6 years now, and they work very well, and they are better than optical mirrors in many ways. Mine are inexpensive backup cameras, so with better "F stop" controls, they will be better than optical mirrors in virtually every way.
This will apparently require paying off some Congresspeople. http://www.autonews.com/article/20140331/OEM11/140339975/tesla-alliance-seek-u.s.-regulators-ok-to-ditch-side-mirrors" onclick="window.open(this.href);return false;
 
dgpcolorado said:
... I drove a Volt for a couple of hours and it was a relief to get back into the spacious, comfortable LEAF. I've never heard of or seen the Mercedes CLA.....

.....I agree that the LEAF hatch could be better designed. But with the extreme tapering, suggested by NeilBlanchard, if I understand his suggestion correctly, it would be difficult

Every body comes in different shapes and sizes. For me the volt was far superior in comfort but I knew it wouldn't last as long with an infant and a planned second child, the leaf seats are all wrong. Not nearly enough leg room, not enough angle to the seat cushion. For my long legs it sucks, I can't use the left cup holder since it bangs my knee. I can't sit in the passenger front seat since my knee hits the bottom corner of the dash right at the joint. I would rather be a passenger in the rear seat. The prius and leaf are both family cars, neither I see as my car. The Mercedes CLA is small (a touch smaller than a volt) and car and driver tested a US version and it was the smallest car they tested. A super low drag version in Europe is said to have 0.23 cd vs the 0.3 car and driver found on the US car.

I really really wish we had waited 3 months to get our prius, that was when the volt $5000 price drop came, for our needs it put the 2 on par price wise. I secretly wish someone would steal our prius but I know that is never going to happen.

The hatch he is referencing is like the insight hatch, and again that one is much better than the leaf. The car at the sides tapers but the hatch doesn't. It's pretty much as wide as it can be at the bumper and is a really nice opening. If it was as deep as the leaf it would be just as easy or even easier to load things into.

Moof said:
Bonus: More motor power above 30 mph. The bottom end is plenty peppy, but just gets sad by 50 mph. How about giving us 100-120 kW of power above 30 mph?

I've heard (can't remember where I read it) that they were looking at a 2 spd transmission, this may help that.
 
minispeed said:
Moof said:
Bonus: More motor power above 30 mph. The bottom end is plenty peppy, but just gets sad by 50 mph. How about giving us 100-120 kW of power above 30 mph?

I've heard (can't remember where I read it) that they were looking at a 2 spd transmission, this may help that.

See http://www.mynissanleaf.com/viewtopic.php?f=27&t=5323 for some dyno curves of the Leaf 1.0. The ramp up in power from 0 to 105 HP from 0 to 25 mph is set by the max torque software limit or max current limit rating of the motor (you can't tell which without talking to someone form Nissan), then the flat plateau is set by the 80 kW limit. The slight slope down in power caused by motor windage losses and other similar speed dependent drag items in the drive train.

A 2 speed transmission lets you get a higher top speed and higher low end torque. It also buys you a little higher efficiency due to reduced motor windage losses in the middle, but only a few percent. The 80 kW drive train limit currently set the performance from 25 to 90 mph, a different gear ratio would not change the motor power, just the speeds at which the max torque/current limits you, and where the motor max RPM limits you.

Changing the gearing to a 2-speed tranny would let you extend that, say from 15 to 120 mph for better low end torque (if the CV joints can take it) and higher top end speed, but doesn't change the fact that you only have 80 kW available and would make no significant difference in the acceleration from 30-60 mph. I personally think the 0-30 mph performance is fantastic for a little econobox family car, but merging onto the highway that is going 55-60 up a modest hill is fairly lackluster.
 
This is what a Cd of 0.235 looks like:

renault-eolab-prototype-photo-639814-s-1280x782.jpg


And the Cd drops to 0.227 with three active elements are deployed - I think those could be made fixed, and get the Cd even a bit lower.

CHR2793.jpg


It has video mirrors (and tiny optical mirrors, too):

ren%2Becolab3.jpg
 
Now that's a nice looking EV! What's the Renault/Nissan relationship again? partners or parent/child company? division of...? Thanks for the pics.

Curt
 
They have the same CEO, and I think they share a lot of engineering and designs. They use the same battery modules.

The Eolab is a plugin hybrid concept, but it is quite close to a production car, and they claim it would cost just $24K, if I recall correctly. It is light weight, but use "normal" construction and non-exotic materials. It has three doors, plus the hatch, to save weight.

I would buy one in a nanosecond!
 
Looks pretty spiffy. I guess I am wondering when we will see a splitting of the Leaf into a family of cars like the Prius did.

Something like that Renault could be similar to a Prius C, small with comfort for 2, and capability for 4 in a pinch. A 20-24 kWh battery pack of denser cells stuffed into a car like that could be a relatively cheap way to get 100-120 mile range for a commuter car.

A 42 kWh pack shoved into a slightly slimmed down Leaf body size gets you a mainstream family car for 5 with decent cargo space with 150-200 mile range.

A 60 kWh pack put in mini-van frame gets you into the large family for 7 passengers with a 150+ mile range.
 
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